// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/gfx/skia_util.h"

#include <stddef.h>
#include <stdint.h>

#include "third_party/skia/include/core/SkBitmap.h"
#include "third_party/skia/include/core/SkColorFilter.h"
#include "third_party/skia/include/core/SkColorPriv.h"
#include "third_party/skia/include/core/SkUnPreMultiply.h"
#include "third_party/skia/include/effects/SkBlurMaskFilter.h"
#include "third_party/skia/include/effects/SkGradientShader.h"
#include "third_party/skia/include/effects/SkLayerDrawLooper.h"
#include "ui/gfx/geometry/quad_f.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/image/image_skia_rep.h"
#include "ui/gfx/shadow_value.h"
#include "ui/gfx/transform.h"

namespace gfx {

SkPoint PointToSkPoint(const Point& point)
{
    return SkPoint::Make(SkIntToScalar(point.x()), SkIntToScalar(point.y()));
}

SkIPoint PointToSkIPoint(const Point& point)
{
    return SkIPoint::Make(point.x(), point.y());
}

SkPoint PointFToSkPoint(const PointF& point)
{
    return SkPoint::Make(SkFloatToScalar(point.x()), SkFloatToScalar(point.y()));
}

SkRect RectToSkRect(const Rect& rect)
{
    return SkRect::MakeXYWH(
        SkIntToScalar(rect.x()), SkIntToScalar(rect.y()),
        SkIntToScalar(rect.width()), SkIntToScalar(rect.height()));
}

SkIRect RectToSkIRect(const Rect& rect)
{
    return SkIRect::MakeXYWH(rect.x(), rect.y(), rect.width(), rect.height());
}

Rect SkIRectToRect(const SkIRect& rect)
{
    return Rect(rect.x(), rect.y(), rect.width(), rect.height());
}

SkRect RectFToSkRect(const RectF& rect)
{
    return SkRect::MakeXYWH(SkFloatToScalar(rect.x()),
        SkFloatToScalar(rect.y()),
        SkFloatToScalar(rect.width()),
        SkFloatToScalar(rect.height()));
}

RectF SkRectToRectF(const SkRect& rect)
{
    return RectF(SkScalarToFloat(rect.x()),
        SkScalarToFloat(rect.y()),
        SkScalarToFloat(rect.width()),
        SkScalarToFloat(rect.height()));
}

SkSize SizeFToSkSize(const SizeF& size)
{
    return SkSize::Make(SkFloatToScalar(size.width()),
        SkFloatToScalar(size.height()));
}

SizeF SkSizeToSizeF(const SkSize& size)
{
    return SizeF(SkScalarToFloat(size.width()), SkScalarToFloat(size.height()));
}

Size SkISizeToSize(const SkISize& size)
{
    return Size(size.width(), size.height());
}

void TransformToFlattenedSkMatrix(const gfx::Transform& transform,
    SkMatrix* flattened)
{
    // Convert from 4x4 to 3x3 by dropping the third row and column.
    flattened->set(0, SkMScalarToScalar(transform.matrix().get(0, 0)));
    flattened->set(1, SkMScalarToScalar(transform.matrix().get(0, 1)));
    flattened->set(2, SkMScalarToScalar(transform.matrix().get(0, 3)));
    flattened->set(3, SkMScalarToScalar(transform.matrix().get(1, 0)));
    flattened->set(4, SkMScalarToScalar(transform.matrix().get(1, 1)));
    flattened->set(5, SkMScalarToScalar(transform.matrix().get(1, 3)));
    flattened->set(6, SkMScalarToScalar(transform.matrix().get(3, 0)));
    flattened->set(7, SkMScalarToScalar(transform.matrix().get(3, 1)));
    flattened->set(8, SkMScalarToScalar(transform.matrix().get(3, 3)));
}

sk_sp<SkShader> CreateImageRepShader(const gfx::ImageSkiaRep& image_rep,
    SkShader::TileMode tile_mode,
    const SkMatrix& local_matrix)
{
    return CreateImageRepShaderForScale(image_rep, tile_mode, local_matrix,
        image_rep.scale());
}

sk_sp<SkShader> CreateImageRepShaderForScale(
    const gfx::ImageSkiaRep& image_rep,
    SkShader::TileMode tile_mode,
    const SkMatrix& local_matrix,
    SkScalar scale)
{
    // Unscale matrix by |scale| such that the bitmap is drawn at the
    // correct density.
    // Convert skew and translation to pixel coordinates.
    // Thus, for |bitmap_scale| = 2:
    //   x scale = 2, x translation = 1 DIP,
    // should be converted to
    //   x scale = 1, x translation = 2 pixels.
    SkMatrix shader_scale = local_matrix;
    shader_scale.preScale(scale, scale);
    shader_scale.setScaleX(local_matrix.getScaleX() / scale);
    shader_scale.setScaleY(local_matrix.getScaleY() / scale);

    sk_sp<SkShader> shader = SkShader::MakeBitmapShader(image_rep.sk_bitmap(), tile_mode, tile_mode, &shader_scale);
    return shader;
}

sk_sp<SkShader> CreateGradientShader(int start_point,
    int end_point,
    SkColor start_color,
    SkColor end_color)
{
    SkColor grad_colors[2] = { start_color, end_color };
    SkPoint grad_points[2];
    grad_points[0].iset(0, start_point);
    grad_points[1].iset(0, end_point);

    return SkGradientShader::MakeLinear(grad_points, grad_colors, NULL, 2, SkShader::kRepeat_TileMode);
}

static SkScalar RadiusToSigma(double radius)
{
    // This captures historically what skia did under the hood. Now skia accepts
    // sigma, not radius, so we perform the conversion.
    return radius > 0 ? SkDoubleToScalar(0.57735f * radius + 0.5) : 0;
}

sk_sp<SkDrawLooper> CreateShadowDrawLooper(
    const std::vector<ShadowValue>& shadows)
{
    if (shadows.empty())
        return sk_sp<SkDrawLooper>();

    SkLayerDrawLooper::Builder looper_builder;

    looper_builder.addLayer(); // top layer of the original.

    SkLayerDrawLooper::LayerInfo layer_info;
    layer_info.fPaintBits |= SkLayerDrawLooper::kMaskFilter_Bit;
    layer_info.fPaintBits |= SkLayerDrawLooper::kColorFilter_Bit;
    layer_info.fColorMode = SkXfermode::kSrc_Mode;

    for (size_t i = 0; i < shadows.size(); ++i) {
        const ShadowValue& shadow = shadows[i];

        layer_info.fOffset.set(SkIntToScalar(shadow.x()),
            SkIntToScalar(shadow.y()));

        // SkBlurMaskFilter's blur radius defines the range to extend the blur from
        // original mask, which is half of blur amount as defined in ShadowValue.
        sk_sp<SkMaskFilter> blur_mask = SkBlurMaskFilter::Make(kNormal_SkBlurStyle,
            RadiusToSigma(shadow.blur() / 2),
            SkBlurMaskFilter::kHighQuality_BlurFlag);
        sk_sp<SkColorFilter> color_filter = SkColorFilter::MakeModeFilter(shadow.color(), SkXfermode::kSrcIn_Mode);

        SkPaint* paint = looper_builder.addLayer(layer_info);
        paint->setMaskFilter(blur_mask);
        paint->setColorFilter(color_filter);
    }

    return sk_sp<SkDrawLooper>(looper_builder.detach());
}

bool BitmapsAreEqual(const SkBitmap& bitmap1, const SkBitmap& bitmap2)
{
    void* addr1 = NULL;
    void* addr2 = NULL;
    size_t size1 = 0;
    size_t size2 = 0;

    bitmap1.lockPixels();
    addr1 = bitmap1.getAddr32(0, 0);
    size1 = bitmap1.getSize();
    bitmap1.unlockPixels();

    bitmap2.lockPixels();
    addr2 = bitmap2.getAddr32(0, 0);
    size2 = bitmap2.getSize();
    bitmap2.unlockPixels();

    return (size1 == size2) && (0 == memcmp(addr1, addr2, bitmap1.getSize()));
}

void ConvertSkiaToRGBA(const unsigned char* skia,
    int pixel_width,
    unsigned char* rgba)
{
    int total_length = pixel_width * 4;
    for (int i = 0; i < total_length; i += 4) {
        const uint32_t pixel_in = *reinterpret_cast<const uint32_t*>(&skia[i]);

        // Pack the components here.
        SkAlpha alpha = SkGetPackedA32(pixel_in);
        if (alpha != 0 && alpha != 255) {
            SkColor unmultiplied = SkUnPreMultiply::PMColorToColor(pixel_in);
            rgba[i + 0] = SkColorGetR(unmultiplied);
            rgba[i + 1] = SkColorGetG(unmultiplied);
            rgba[i + 2] = SkColorGetB(unmultiplied);
            rgba[i + 3] = alpha;
        } else {
            rgba[i + 0] = SkGetPackedR32(pixel_in);
            rgba[i + 1] = SkGetPackedG32(pixel_in);
            rgba[i + 2] = SkGetPackedB32(pixel_in);
            rgba[i + 3] = alpha;
        }
    }
}

void QuadFToSkPoints(const gfx::QuadF& quad, SkPoint points[4])
{
    points[0] = PointFToSkPoint(quad.p1());
    points[1] = PointFToSkPoint(quad.p2());
    points[2] = PointFToSkPoint(quad.p3());
    points[3] = PointFToSkPoint(quad.p4());
}

} // namespace gfx
